Many medicinal inhalants have temperature-dependent shelf lives that dictate that the medicaments be stored at a particular temperature to maintain a usable life of the medicament. Examples of commonly used medicaments having temperature-dependent shelf lives include insulin, interferon, etc. In an institutional setting, such as a home or medical treatment facility, these types of medicaments can be stored in appliances such as refrigerators with little trouble. However, problems arise when a patient attempts to store or travel with the medicament in environments having temperatures above or below the recommended storage temperature of the medicinal inhalant.
Thus, while many patients should carry such medicaments with them throughout the day, removing the medicaments from a controlled storage environment, such as a refrigerator, can result in the medicaments prematurely expiring. This can serve to deter patients from carrying such medicaments with them, or can result in a patient's medicament expiring prematurely without patient knowledge.
Several systems have been developed in an effort to provide portability to inhalants having limited, temperature-dependent shelf lives. One known method includes providing medicament inhalers having medicament in a dry powder form that can be mixed with a fluid prior to dispensing the medicament to the patient. As the medicament is stored within the inhaler in a dry form, the shelf life of the medicament is not as temperature-dependent as if stored in a liquid form. While this solution has met with some success, the requirement of mixing the powder with a liquid prior to administering the inhalant to a patient has necessitated the use of relatively sophisticated internal mixing systems which result in inhalers that may be inconvenient, unreliable and overly complex. Also, some types of medicines are not well suited to be reduced to powdered form.
Another attempt to address these problems has been by providing cold packs that are placed adjacent a reservoir of medicament in drug delivery systems in an attempt to cool the medicament stored in the reservoir. This system has proved problematic in that the medicament can become overly warm without the user become aware of this fact when the cold packs lose their cooling capacity during use. This system is also very dependent on the outside environment, as a very hot environment can result in the cold packs losing their cooling capacity more quickly than in a cooler environment. Also, such systems are not generally capable of controllably cooling a medicament in a reservoir to a variable range of temperatures, but will rather only lower a temperature of a medicament to some equilibrium temperature dependent on the cooling capacity of the cold packs, the size of the medicament reservoir, etc.
Accordingly, while many patients can benefit from a system that provides portability to temperature-dependent inhalants, current solutions to this problem have proven ineffective for a variety of reasons.